Model of two-dimensional electron gas formation at ferroelectric interfaces

Abstract

After the discovery of a 2D electron gas at the interface between LaAlO${}_{3}$ and SrTiO${}_{3}$, a great effort has been devoted to the investigation of possible routes to manipulate this system in order to exploit its interesting properties in practical applications. In this work the authors use a Landau model to show that a similar 2-dimensional electron gas may spontaneously form at ferroelectric interfaces. Unlike in the case of the LaAlO${}_{3}$/SrTiO${}_{3}$ interface, the properties of this system can be tuned in a nonvolatile way with the application of an electric field through its coupling with the ferroelectric polarization. This, for instance, would allow to induce a metal/insulator transition or to switch between an electron and a hole gas using an electric field. Such properties open new avenues for the use of 2D electron gases in oxide interfaces.